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Feb. 17. '19225.l 1,526,378

F. H.Ro YcE BRAKE FOR ROAD VEHICLES Filed May 14, 1924 2 Sheets-Sheet 1 FREDERIC/f HENRY/Fvrie @Womad Z F. H. ROYCE BRAKE FOR ROAD VEHICLES Feb. 17. 1925.V

2 Sheets-Sheet 2 Filed May 14, 1924 Patented Feb. 17, 1925.

UNITED STATES PATENT OFFICE.

FREDERICK HENRY ROYCE, OF DERBY, ENGLAND, ASSIGNOR TO ROLLS ROYCE LIM- ITED, 0F DERBY, ENGLAND.

l y BRAKE FOR ROAD VEHICLES.

Application filed May 14, 1924.

To all whom 'it may concern:

Be it known that I, FREDERICK HENRY llo-Yon, residing at Derby, England, a subject of the King of Great Britain and 1reland, have invented rertain new and useful improvements in Brakes for Road Vehicles, of which the following is a specification.

This invention has reference to brakes for road vehicles and has for its object the utilization of the rotation of the vehicle Wheels on the principle commonly called a servo brake for applying pressure on the brakes and also the braking of all the wheels of the vehicle.

i-rccording to this invention a sha-ft (hereinafter called the driving clutch member shaft) is geared to a moving shaft of the vehicle and is always in motion when the vehicle is travelling, and another shaft (hereinafter called the driven clutch member shaft) when rotated through a certain arc operates the rear wheel brakes. Motion communicated from the driving to the driven clutch member shafts through the instrumentality of a friction clutch, preferably a multi-plate clutch, so that the pressure on the rear wheel brakes varies with the friction produced in the clutch. A lever, preferably a foot pedal operable by the driver, actuates mechanism whereby in the first instance a direct mechanical brake is applied lo the front wheels, and immediately upon the brake being resisted by the drum or other device of said front wheel brakes, the clutch is automatically closed and thereby operates the brakes of the rear wheels. A stop is provided which prevents the driven clutch member shaft from rotating to such an extent as to completely wear out, the frictional parts of the rear brakes.

An additional lever, )referably hand operated, :is connected to the mechanism and is capable of operating the rear wheel brakes independently of the servo mechanism, said lever being adapted to provide for further application of the rear wheel brakes when the driven clutch membe abuts against the stop above mentioned, with the result that warning is given of the state of the rear wheel brake surfaces before they become ineffective.

If desired the converse arrangement can be adopted, to wit, the servo device operating the front Wheel brakes.

Serial No. 713,283.

An example of my invention is illustrated in the accompanying drawings in which t- Fig. l is a sectional view of the servo mechanism, F ig. 2 an end elevation of Fig. 1 viewed from the right hand, and Fig. 3 a section of Fig. l on line X-X- The levers, etc., are shown in the positions they would occupy when both brakes are off. Fig Ll 1s a sectional detail view showing certain levers hereinafter referred to. Fig. is a section on line 5-5 of Fig. e. Fig. 6 is a sectional detail view of elements for preventing excessive rotation of the driven clutch member shaft, the parte in section being taken on line 6--6 of Figs. i' and 8 which latter figures are edge views of the elements referred to. F ig. 9 is a sectional detail view of a rod f3 hereinafter described.

ln said drawings a designates the gear box of an automobile road vehicle (part only shown); al `a cylindrical extension of the gear box integral therewith and a2 a cylindrical casing for the servo device attached to the said extension by bolts and nuts a3 and a* respectively and having` gaps in its walls for passage of the levers hereinafter described. Between the extension al and casing u? are held the flange b5 of the niember and the member 02 both hereinafter referred to. fr. designates an end cover secured to casing a2 by bolts and nuts a and al respectively.

Z) designates a. shaft (hereinbefore referred to as the driving clutch member shaft) having formed thereon and integral therewith a flange b1 and a drum 62. Said shaft l; rotates in journals or bearings o supported by the annular member v264 above mentioned fixed to the casing al by means of the flange b5, and carries a worm pinion Z2 which meshes with a worm wheel l mounted on a shaft 3 in the gear box-which is always in rotation when the car is in motion. On the said drum b2 are formed internal axial serrations. lf designate annular discs provided on their faces with friction material and having serrations formed on their outer circumference engaging with the serrations on the said drum b2.

c designates a hollow shaft (hereinbefore referred to the driven clutch member shaft) having bearing in an annular member c1 which is bolted to the member' c2 above mentioned through holes 01 (Fig. 6) and lil also in a memberI fl hereinafter described. '03 is a collar or flange on the shaft o abutting against an annular member which in turn abuts against the member' @1 @n the outer circumference of the larger end of the shaft c axial serrations 0" are formed, and c are annular plates having on their inner circumference serrations which engage the serrations 05. c7 is an annular plate having scrrations on its inner circumference also engaging with the serrations o8 and 01S designate dogs extending respectively and alternately from the members c1 and c7 to limit the possible rotational movement of shaft c as predetermined; sec more parti-cularly Figs. G and l'.

(Z designates av lever mounted on the shafi c and having serrations or dogs (Zw t' formed Within its boss which engage like serrations all formed on the shaft butl with Y n amount of back-lash or lost motion as shown in Figure 3, this lever being connected through a rod (Z2 to the rear Wheel bralces (not shown). d, (Zt and (Z5 designate respectively a bolt7 nut and spacing sleeves comiecting the ro-:l om to the lever Z and forming extensions for the purpose hereinafter explained.

d is a second le "er, formed two plates bolted together at (Z7 Si) and freely mounted on the boss of lever (I and connected through a rod (ZS to an operating member such as a hand lever (not shown). The effect of this arrangement is that ifE for any reason, the servo brake does not operate. the hand brake lever ivill act on lover fl and the two plates thereof will bear on the projections formed by bolt (Z3 and so operate lover d.

c designates a bush rotatably mounted on the shaft ivith end thrust hearings c" and of at its ends. e designates a lever mounted on and rigidly connected to the bush e by means of a key @mand bolt e (Fig. t), said lever e3 being connected through the rod c* to the front Wheel brakes (not shown); e5 is another lever mounted on the bush e anc having spiral serrations c within its boss ci' aging similar spiral seri-ations cw 9)5 in the bush c, these serraiions being so inclined that on said lever @5 being` rocked7 if the bush is prevented from rotating the boss ofsaid lever will move aiahy to the right in Fig l. The said lever e5 connected through rod c7 to the pedal brake lover (not shown).

j designates a bowl shaped presser plat which, when brought into action as herein* after explained, forces the friction discs o" and c together: f1 is a Washer which slices freely in the shaft c and bears against a central projection extending` from the presser plate; f3 is a rod threaded at both ends and ft is a nut engaging the thread on t rod f3 at ono end. f5 designates a helical ig acting between the Washer f1 and a shoulder fm on the shaft c; f6 is a squared portion of the rod litting a squared portion of the bore of the shaft c; (Fig. 7) fl is an end bearing cap supporting the adjacent end of the shaft .e and capable of sliding' axially in a bush ,f8 in the end of the casing extension a2; /lq and flo are respec tively a nut and lock nut engaing the thread at the otner end of the rod.

il. stop to prevent the lever el* from moving beyond a prescribed limit is formed by the shape of a cut away portion of the casing c? at y and the casing is also cut away as at 71 to al lovf the lever c5 to move to a further extent.

The operatir i of the mechanism described as folloivszs y T he shaft l), drinn '32 and friction plates ZJ are aliva 's rotating freely While the vehicle On -ie pedal brake lever being operated, the lf i ff "oclicd and the bush c rotated, cari l. it lever c3 which through rod e* apolies tile forward Wheel brakes. This arrests the movement of lever c and hence of the bush c and lever e5. Thereupon the aid lever e5 by reason of the spiral serrans e and e moves axially to the right in lying with it the cap f7, rod f rlhis closes the friction :s shaft c to rotate7 carrying l i he lever Z which through the rod df ivheel brakes.

in the predetermined ratio.

1 should occur in the front in whereby' the lever e f'otatet movement will be arl ,s oi if and hence the rear Wheel i l. i l.

i ie throivn out of action.

, omer hand any (,lefeet should occur in the vvheel brake mechanism ori.

oivinjij to eti-:ce ivo vez of the shoes or other c fri :on incr bers, the lever t? should not be arresteth the rotational movement of the slr-ft c vill be arrested by the dogs cs and e front vfhee brakes vvill not be thrown out of action. These dogs also stop the rotation of the shaft z' if the car is moving backl when the servo device will be out of n. Further, rear wheel brakes can, in case l nv such defects and also when the car is actuate lever (l and operate ivheel bralcs.

A claim secure by Letters Pat-ent of Vthe States is four-Wheel brake system for road l. A. vehicles comprising in combination a member permanently geared to a moving part of the vehicle, an element which when roas my invention, and de-v Cil llt)

tated through a given are applies brakes on one pair of wheels only, a friction device whereby the motion of the said member can be communicated to said element, mech aaism for applying brakes on the other pair of wheels, and means for operating by a single manual action the friction device and the mechanism of the brakes of said other pair of Wheels.

2. ln a four-wheel brake system for road vehicles` a servo device, direct-acting brakeapplying means, a sleeve, a member Whereon said sleeve is mounted for simultaneous rotational movement and relative axial movement, and means whereby one of such movements effects the direct action of the brake applying means and the other of such movements effects the application of the servo device.

3. In a four-Wl1eel brake system for road vehicles, the combination of a rotating drum permanently geared to a moving part of the vehicle and carrying one element of a friction device, a shaft extending Within said drum and carrying the other element of said friction device, a lever carried by said shaft and adapted to apply the brakes of one pair of Wheels, a bush freely mounted on the said shaft, a second lever mounted. on and rigidly secured to such bush and adapted when operated lo apply the brakes of the other pair of wheels, a third lever mounted on said bush and adapted to be manually operated, a sliding member caused to move axially by the third lever, a rod attached to said sliding` member to move therewith, a spring bearing against said rod to oppose its movement, and a presser plate secured to said rod and adapted to close y(he elements of the friction device.

1l. A four-Wheel brake system for road vehicles, con'iprising, in combination, a shaft permanently `geared to a moving part of the vehicle; a second. shaft; means mounted on the second shaft and connected to apply brakes on one pair of Wheels only; a friction device whereby the movement of the first-mentioned shaft can be communicated to said second shaft; a lever mounted on said second shaft with an amount of back lash and connected to apply brakes on the other pair of Wheels; a second lever freely mounted in relation to the said second shaft and adapted to actuate the iirst lever under predetermined conditions; and means under manual control connected to operate said second lever.

5. A four-Wheel brake system, according to claim Ll, in which stop means are provided adapted to arrest movement of the second shaft irrespective of its arrest by the resistance of the brake mechanism, and also adapted to arrest its movement when the vehicle is travelling backwards.

(i. A four-Wheel brake system, according to claim el, in Which the means mounted on the second shaft and connected to apply brakes to one pair of Wheels only embodies a lever; and in which a stop is provided adapted to arrest the movement of that lever at a predetermined point irrespective of its arrest by the resistance of the brake mechanism.

T. A, four-wheel brake system, according to claim 4, in which the means mounted on the second shaft and connected to apply brakes to one pair of lwheels only, comprises a bush rotatably 'litted on said shaft. and a lever keyed to said bush; and in which a stop is provided adapted to arrest the movement of said keyed lever at a predetermined point irrespective of its arrest by the resistance of the brake mechanism.

8. A four-wl1eel brake system for road vehicles, comprising, in combination, a shaft permanently geared to a moving parl` of the vehicle; a second shaft; a bush rotatably mounted on the second shaft; a lever keyed to the bush and connected to apply brakes on one pair of Wheels only; a pedaloperated lever mounted on said bush to rotate the same and thereby actuate the first lever; means for communicating the rotary movement of the iirst shaft to the second shaft; and a lever mounted on the second shaft With an amount of back lash and connected to apply brakes on the other pair of Wheels.

In Witness whereof l have signed this speciiication.

FREDERCK HENRY ROYCE. 

